A Two-Dimensional Displacement Measuring Device Based on Diffraction Grating

Abstract

A two-dimensional displacement measurement device based on a diffraction grating involves an ultra-precise displacement measurement technology and a grating displacement measurement system, which consists of two parts: a scale grating and a reading head. Detection components, Z-direction detection components, and signal processing components; the device is based on the principle of Michelson interferometer and the principle of multi-diffraction grating interference to realize the simultaneous measurement of X-direction and Z-direction displacement, with simple and compact structure, small size and strong anti-interference ability As well as the advantages of uncoupling of X-direction and Z-direction measurement, it can achieve nanometer or even higher measurement resolution, and can be applied to multi-degree-of-freedom high-precision displacement measurement.

Description

technical field [0001] The invention relates to an ultra-precise displacement measurement technology and a grating displacement measurement system, in particular to a two-dimensional displacement measurement device based on a diffraction grating. Background technique [0002] In recent years, ultra-precision measurement has become a research hotspot in the field of measurement in the world. Considering the influence of factors such as measurement range, accuracy, system size, and working environment, the demand for high-precision measurement using a small-volume multi-degree-of-freedom measurement method is becoming more and more prominent in modern displacement measurement. In the field of semiconductor processing, the positioning accuracy and motion accuracy of the mask table and workpiece table in the lithography machine are the main factors that limit the line width of semiconductor chip processing. In order to ensure the positioning accuracy and motion accuracy of the m...

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Problems solved by technology

In this group of patents, when the reading head moves in the Z direction relative to the scale grating, the range of the interference area becomes smaller, which is not conducive to the measurement of a larger range in the Z direction

[0008] The patents CN102865817A (disclosure date January 9, 2013) and US8604413B2 (disclosure date December 10, 2013) of Mitutoyo Corporation of Japan propose a structure of a two-dimensional displacement sensor, which can realize multidimensional displacement measurement, but The whole system adopts the transmission method, and uses optical devices such as prisms for refraction, so the system is relatively large

[0009] In the patent CN103604376A (published on February 26, 2014) by Hu Pengcheng, a scholar of Harbin Institute of Technology, a kind of anti-optical frequency aliasing grating interferometer system is proposed, and the dual-frequency laser emitted by the laser is transmitted separately in space. setting, eliminating the optical frequency aliasing and the corresponding periodic nonlinear error, and can realize the measurement of three-dimensional displacement; in the patent CN103644849A (disclosure date March 19, 2014) of Harbin Institute of Technology scholar Lin Jie et al., by introducing the self The principle of collimation proposes a three-dimensional displacement measurement system, which can achieve a large range of Z-direction displacement measurement, but due to the large number of beam splitting times, it is not conducive to improving the quality of the interference signal

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